Uranyl fluoride luminescence in acidic aqueous solutions

Luminescence emission spectra and decay rates are reported for uranyl species in acidic aqueous solutions containing HF or added NaF. The longest luminescence lifetime, 0.269 {+-} 0.006 ms, was observed from uranyl in 1 M HF + 1 M HClO{sub 4} at 296 K and decreased with increasing temperature. Based on a luminescence dynamics model that assumes equilibrium among electronically excited uranyl fluoride species and free fluoride ion, this long lived uranyl luminescence in aqueous solution is attributed primarily to UO{sub 2}F{sub 2}. Studies on the effect of added LiNO{sub 3} or Na{sub 2}WO{sub 4}{center_dot}2H{sub 2}O showed relatively weak quenching of uranyl fluoride luminescence which suggests that high sensitivity determination of the UF{sub 6} content of WF{sub 6} gas should be feasible via uranyl luminescence analysis of hydrolyzed gas samples of impure WF{sub 6}

Mid-Miocene cooling and the extinction of tundra in continental Antarctica

A major obstacle in understanding the evolution of Cenozoic climate has been the lack of well dated terrestrial evidence from high-latitude, glaciated regions. Here, we report the discovery of exceptionally well preserved fossils of lacustrine and terrestrial organisms from the McMurdo Dry Valleys sector of the Transantarctic Mountains for which we have established a precise radiometric chronology. The fossils, which include diatoms, palynomorphs, mosses, ostracodes, and insects, represent the last vestige of a tundra community that inhabited the mountains before stepped cooling that first brought a full polar climate to Antarctica. Paleoecological analyses, 40Ar/39Ar analyses of associated ash fall, and climate inferences from glaciological modeling together suggest that mean summer temperatures in the region cooled by at least 8°C between 14.07 ± 0.05 Ma and 13.85 ± 0.03 Ma. These results provide novel constraints for the timing and amplitude of middle-Miocene cooling in Antarctica and reveal the ecological legacy of this global climate transition

Fifteen years controlling unwanted thoughts: A systematic review of the thought control ability questionnaire (TCAQ)

Thought control ability is a vulnerability factor implicated in the etiology and maintenance of emotional disorders. This manuscript aims to systematically review the use and psychometric performance of the Thought Control Ability Questionnaire (TCAQ), designed to assess people's ability to control unwanted thoughts. Three electronic databases were searched for papers administering the TCAQ published in indexed peer-reviewed journals. Data (participants characteristics, country, study design, etc.) were extracted from the results for qualitative synthesis. The TCAQ's content validity, dimensionality, internal consistency, test-retest reliability, convergent/divergent validity, floor/ceiling effects, and interpretability were summarized. Two reviewers independently screened articles and assessed quality taking COSMIN criteria into account. Finally, the review included 17 papers. The TCAQ has been administered to healthy individuals, students, and adult patients, in six languages from nine countries. We found that the TCAQ, and its shorter versions, demonstrate robust reliability and adequate content validity. Of interest is the TCAQ's capacity to predict performance in diverse experimental tasks focused on thought control. The TCAQ unidimensionality has been supported in exploratory and confirmatory factor analyses. Regarding construct validity, the TCAQ is significantly related to a wide range of psychopathological measures of anxiety, worry, depression, obsessive-compulsive symptoms, etc. However, as only a few of the included studies had a longitudinal design, we are unable to draw firm conclusions about the measure's temporal stability. Moreover, psychometric aspects such as factorial invariance across different samples have not been analyzed. Despite these limitations, based on available psychometric evidence we can recommend using the TCAQ for measuring perceived control of unwanted thoughts

Gamma-ray Observations Under Bright Moonlight with VERITAS

Imaging atmospheric Cherenkov telescopes (IACTs) are equipped with sensitive photomultiplier tube (PMT) cameras. Exposure to high levels of background illumination degrades the efficiency of and potentially destroys these photo-detectors over time, so IACTs cannot be operated in the same configuration in the presence of bright moonlight as under dark skies. Since September 2012, observations have been carried out with the VERITAS IACTs under bright moonlight (defined as about three times the night-sky-background (NSB) of a dark extragalactic field, typically occurring when Moon illumination > 35%) in two observing modes, firstly by reducing the voltage applied to the PMTs and, secondly, with the addition of ultra-violet (UV) bandpass filters to the cameras. This has allowed observations at up to about 30 times previous NSB levels (around 80% Moon illumination), resulting in 30% more observing time between the two modes over the course of a year. These additional observations have already allowed for the detection of a flare from the 1ES 1727+502 and for an observing program targeting a measurement of the cosmic-ray positron fraction. We provide details of these new observing modes and their performance relative to the standard VERITAS observations

Efimov physics beyond universality

We provide an exact solution of the Efimov spectrum in ultracold gases within the standard two-channel model for Feshbach resonances. It is shown that the finite range in the Feshbach coupling makes the introduction of an adjustable three-body parameter obsolete. The solution explains the empirical relation between the scattering length a_- where the first Efimov state appears at the atom threshold and the van der Waals length l_vdw for open channel dominated resonances. There is a continuous crossover to the closed channel dominated limit, where the scale in the energy level diagram as a function of the inverse scattering length 1/a is set by the intrinsic length r* associated with the Feshbach coupling. Our results provide a number of predictions for non-universal ratios between energies and scattering lengths that can be tested in future experiments.Comment: 6 pages, 4 figures; final versio

Genomic retrospective evaluation of 20 years of selection in Italian Holstein bulls for feet and legs trait

Under strong directional selection,allelefrequencies rapidly change,allowing the identificationof genomic regions carrying genes and variantsthat control selected traits, as production, functional and morphologicaltraits. Here we searched selection sweeps by birth date regression on EBVs and the analysis of changes in allele frequencies. Genomic retrospective evaluation of recent selection wasperformed in 2918 Italian Holstein bulls born between 1979 and 2011. Genotypedata from SELMOL, PROZOO and INNOVAGEN projects were used.Estimated Breeding Value (EBVs) for 32 traitswereprovided by the Italian Holstein association (ANAFI). Bulls were genotyped with BovineSNP50 v.1 and BovineHD SNPchips. SNPs positions were updated to UMD3.1 using SNPchiMp v.3. Genotypes were imputed using BEAGLE (v.3.3.4) to obtain HD genotypes for all individuals. After quality control, a total of 2918 animals and 613,956 SNPs were included in the working dataset. Birth date regressed on Feet and LegsEBVshowsa strong positive trend in the birth date interval analyzed. To detect genomic regions involved, we first identifiedPLUS- and MINUS-variantanimalsfor the target EBV over the total year range (134 bulls, group OVERALL)and within each birth year (130 bulls, group BY_YEAR). Then,SNP allelic frequencies, within each group,wereobtainedfor PLUS and MINUS variantspools and the absolute allele frequency difference (delta)was calculated. Mean delta valueswere estimated in overlapping sliding windows of 50 SNPs.Only windows with the mean delta above the 75th percentile + 1.5*Interquartile rangewere retained. Only overlapping regions between OVERALL and BY_YEAR group were retained. These regions cover the 0.84% of the total windows analyzed.Among these, two regions seem particularly interesting. The ~686Kb region on BTA10 (from position 62,578 to 63,264 Kb) had the highest mean delta on BY_YEAR. The~417Kb region onBTA20(from position 40,738 to 41,155 Kb)had thehighest mean delta on OVERALL.Bioinformatic analysis is underway to identify candidate genes, QTLsand metabolic pathways under selection for this trait